On May 30, 2014, the U.S. Court of Appeals for the D.C. Circuit struck down U.S. EPA’s attempt to limit the jurisdictional scope of the Sixth Circuit’s 2012 decision inSummit Petroleum Corp. v. EPA. In Summit, the Court held that “EPA’s determination that the physical requirement of adjacency [for purposes of aggregating multiple emission sources as a single “major source”] can be established through mere functional relatedness is unreasonable and contrary to the plain meaning of the term ‘adjacent’” (click here to read more about the decision). Two months after the decision, the Director of EPA’s Office of Air Quality issued a memo to each of the Regional Air Directors explaining that the Summitdecision would only apply to states within the Sixth Circuit – Kentucky, Michigan, Ohio and Tennessee.

An association of resource extraction and manufacturing companies challenged the memo, claiming that the memo’s directive would leave facilities outside of the Sixth Circuit at a competitive disadvantage. The D.C. Circuit agreed, and held that EPA could not limit Summit’s application.